Manufacture of incandescent electric lamps



(No Model.)

T. A. EDISON. M'ANUFAGTURE OP INGANDESGENT ELECTRIC LAMPS.

No. 438,807. Patented Oct. 14, 1890.

- UNITED STATES PATENT OFFICE.,

rlvllOMAS A. EDISON, OF LLEWELLYN PARK, NEW` JERSEY.

MANUFACTURE OF INCANDESCENT'ELECTRIC LAMPS.

SPECIFICATION forming part of Letters Patent No. 438,307, dated October 14, l890. Application tiled July 147,1886. Serial No. 208.245. (No model.)

To all whom, it 'may concern:

Be it 'known that I, THOMAS A. EDISON, of Llewellyn Park, in the county of Essex and State of New Jersey, have invented a new and useful Improvement in Processes of Manufactu ring Incandescent Electric Lamps, (Case No. (569,) ot which the following is a specifica- The object ot my invention is to produce in the inclosing-globe of an incandescent electric lamp a high vacuum free from mercuryvapors and from moisture and watery vapors.

The process of exhaustion heretofore followed in the ymanufacture of these lamps is by the use of a Sprengel mercury-vacuum pump, and during the-operation of exhaustion by the pump the carbon iilament of the lamp is heated to very high incandescence, the object ot' such heating being to expel certain gases and vapors which were supposed to be occluded or contained in the pores of the carbon. l have found that in the operation of the pump vapors of mercury pass therefrom to the lamp, where they remain, leaving an atmosphere due to the vapor tension of mercury instead of the very high vacuum which is essential for very longlife and high economy in use of the lamp. I have also found that the amount of gases occluded in the carbon filament is so small as to be ot' no practical consequencev in impairingthe vacuum, but that the fluids expelled from lthe lamp by heating the filament came, not from the ilament itself, but from the inner surface of the glass of the globe, where such uids adhere until driven off by heat. The heating of the filament then served to heat the glass, so as to drive off its gases and vapors, and it is this that makes it necessary to bring the filament to such a very high incandescence,

higher than that at ywhich it is intended to be brought in use. Such extreme heating of coursev may affect the carbon injuriously in some cases, and tends,` also, to diminish the length of time for which it can be used.

My invention then relates, iirst, to a method and apparatus for preventing the mercuryvapors from entering the globe, and, second, to a method and apparatus for removing the moisture and watery vapors from the globe, these methods andapparatuses being 'each a part of the complete process and apparatus Whose aim is to produce, as nearly as possible, a perfect vacuu m in the lamp-globe. Apparatus embodying my invention is illustrated in the accompanying drawings.

Figure l is a view in elevation of complete apparatus embodying said invention; Fig. 2, a similar view with a dierent arrangement for getting rid of the moisture, and Fig. 3 a View of a lamp provided with still other means for this purpose.

Referring to Figs. l and 2, A is a Sprengel pump. a b c dare tubes or receptacles situated between the pump and the lamp B which is to be exhausted. C is a heatinglam-p, from whose chimney a metal tube D extends, which surrounds the electric lamp B, having an aperture for the exhaust-tube thereof.

ln Fig. l., E is a chamber, in which is placed a spiral ot iron wire e, having electrical circuit-connections to enable it to be heated to incandescence. F is a bulb containing phos- `phoric anhydride or other moisture absorbent,

which may be used, ify desired.

Tube b contains a substance which is an absorbent ot mercury-vapors, or which combines chemically with such vapors. l prefer to use iodine, chlorine, or bromiue, or an iodide, chloride, or bromide.

Tubes a., c, and tl contain a substance which absorbs or combines chemically with gases or vapors arising from the substance contained in b. In the case of iodine in b antimony or bismuth may be placed in the tubes on either side thereof, or quicklime may be used in the case of chlorine or bromine. A salt of iodine lmay be used in b, which gradually gives oft vapors of iodine, or a chloride which gives oft free chlorine gradually, or a chloride that gives off its chlorine slowly by a gentle heat, (which may be applied to the exterior of the tube) such as sesquichloride of chromium. An inert porous materiahlike charcoal, saturated With chlorine or equivalent gas, may be employed.

In a c cl other substances than those above named may be used-such as metals, as copper, zinc, and ironwhich combine with chlorine; orabsorbent substances may be used, as oxides, magnesia, charcoal, and other inert substances which absorb gases in their pores.

The pump A being in operation, the mer- IOO cury-vaporlwhich flows therefrom' toward the electric lamp B and heats t-he glass thereof,

so as to drive olf the gases and vapors, principally watery vapors, which adhere thereto. Some of these gases are immediately drawn olf by the pump. The water is either absorbed by the phosphoric anhydride or is de the iron spiral inte Aits elements,y

composed by the oxygen combining with the iron, while the-hydrogen, owing toits great mobility, is

v readily removed by the pump.

Instead of heating thev iron by the electric current, the arrangement shown in Fig. 2 may be employed. The receptacle G contains parL ticles of iron or other suitable metal, and

y these are heated by gas or other burners H,

so that they decompose the water and take up its oxygen, as just explained; or the arrangement seen -in Fig. 3 may be used. Here the lamp has a small iron-wire loop vI placed Within it, the ends of the wire being twisted around or otherwise attached to the copper leading in wires. Current being passed through the lamp, the iron is heated to incandescence and the effect on the Water in the lamp is the same as before. The heating is then continued until the wire breaks at some point, after which a magnet is applied to the outside of the lamp and the two parts of the wire are drawn apart d'own into thebottom of the lamp, where they remain after the lamp is sealed, as shown by the dotted lines. All these operations having been finished and the lamp being exhausted to a very high vacuum free from 'mercury-vapor and from moisture, it islsealed otl'from the pump at f, and is then ready for use.I l

I do not claim herein heating the lamp externally to drive olf the vapors and gases from the glass during the exhausting process, since thisl is claimed in my patent, No. 411,018, dated September 18, 1889; neither do I yclaim the lamp provided with a non-mercurial high vacuum, since thisA isl claimed in my Patent No. 411,018, dated Sept. 18, 1889; neither do I claim the special devices illustrated in Figs. 2 and 3; but I reserve these for other applications,

` What I claim istric lamps by mercury-pumps, which consists in taking up the vapors from the pump bya material-placedv between the pump and the lamp and taking .up the gas or vapor from such material by other materials.K 2. The within-described improvement in the method of exhausting incandescent electric lam ps by mercury-pumps, which consists in heating the lamp to removethe gas and vapor therefrom and decomposing the watery vapor, its hydrogen being removed by the pump and its oxygen taken up by material provided for the purpose. q

for exhausting an incandescent electric lamp,

Aof a' material situated between the pump and Tthe lampcapable of absorbing or combining With mercury-vapors, and a of absorbing vor combining vapors arising from such mercury-absorbing material, substantially as set forth.

4. The combination, with a Sprengel pump for exhausting an incandescent electric lamp, of means for heating the lamp, anda material for decomposing the watery vapors expelled from the lamp by such heating,sub stantially as set forth. l

5. The combination, with a Sprengel ump for exhausting an incandescent electric mp, of iron in a chamber or receptacle, connected with the lamp, means for heating the lamp, and means for heating thejron, substantially as set forth.

6. The within-described improvement in the method of exhausting incandescent electric lamps by mercury-pumps, which consists in taking up the vapors from said pump, by a material placed between the pump and the lamp, heating thelamp and decomposing the watery vapor driven therefrom, its oxygen being taken up by a material provided for the purpose and its hydrogen being removed by the pump.

7. The combination,with a Sprengel pump for exhausting an incandescent electric lamp, of a material situated between the pump and the lamp for taking up the vapors which arise from the pump, lamp, and a material for decomposing the heating, substantially as set forth.A

This specification signedand witnessed this 15th day of July, 1886.

. THOS. A. EDISON. Witnesses: J

WM. PELZER,

A. W. KIDDLE.

'f 1. The within-describedv improvement in the method of exhausting incandescent elec- The combination, with a Sprengel pump materialcapable with the gas ion watery vapors expelled from the lamp by such- 1ro means for heatingA the y It is hereby certified that in Letters Patent No.'438,307, granted October 14, 1890,

upon the applicationv of Thomas A. Edison, of Llewellyn l5ark, New Jersey, for an improvement in The Manufacture of Incandescent Electric Lamps,. an error appears in the printed specification requiring the followingicorrection: In lines 56-57, page 2,

the words and figures Patent No. 411,018, dated September 18,1889,shonld read Application No. 667 (Serial No. 208,243) 'and that the Letters Patent should be read with this correction therein that the same may conform to the record. of the casein the Patent Oce. I

Signed, countersigned, and sea-led this 25th day of November, A. D. 1890.

[SEAL] cYnUs BUSSEY,

Assistant Secretary ofthe Interior. Countersigned:

C. E. MITCHELL,

Commissioner of Patents.

It is hereby certified that in Letters Patent No. 438,307, granted October 14, 1890,

upon the application of Thomas A. Edison, of Llewellyn Park, New Jersey, for an improvement in The Manufacture of Inoandeseent Electric Lamps, an error appears in the printed speeication requiring the following correction: In lines 56-57, page 2, the words and gures Patent No. 411,018, dated September 18, 1889,7 should read Application No. 667 (Serial No; 208,243) and that the Letters Patent should be read with this correction therein that the same may conform to the record of the ease in the Patent Ofee. i

Signed, oountersigned, and sealed this 25th day of November, A. D. 1890.

[SEAL] oYRUs BUssEY,

Assistant Secretary` of the Interior. Countersigned:

C. E. MITCHELL,

Commissioner of Patents. 

